It is a prized possession that the world only gets to see a few days a year - the rest of the time is sits protected in the garage. Insurance products exist that understand both the limited exposure from low-use vehicles and the importance of proper repair if damaged.
In today's litigious society, there are a variety of "what if" scenarios that need to be addressed that are not traditionally covered in another policy - for example, you own a piece of land for a future home build - someone taking a shortcut through the lot and sprains an ankle becomes you're problem.